Conventional commercial methods for making hydrochloric acid (HCl in water) include, (1) the formation of acid during the chlorination of aromatic or aliphatic hydrocarbons, (2) the reaction of a chloride salt with sulfuric acid, (3) the combustion of hydrogen and chlorine according to the flame furnace method, or (4) the Hargreaves method. None of these methods captures the potential energy of the exothermic reaction between hydrogen and chlorine to optimize the energy efficiency of the manufacturing method.
Similarly, conventional methods for making sodium hydroxide consume energy while creating waste hydrogen and chlorine. By combining the manufacture of HCl and NaOH, and by using a fuel cell, significant savings can be readily achieved.